: I think she whisped it away to somewhere secure enough to allow them time to
: destroy the reactors and /really/ ensure that Halo isn't activated.
: Perhaps the POA?

: Why did 343GS infiltrate the POA?

Think for a second, if MC put the index in the slot then it would still be there and MC or the 343GS would pull it out. IF it was a hologram of the index that means that the real index is still in the control room. But it's not. Cortana clearly states and talks about how the moniter can't activate Halo without the index. If the Index Cortana had was a hologram then then Halo would tbe started up. I am not sure but I think there may be some Virus in Cortana.